Decibels (dB) * Decibels (dB)

Reference Type * Ratio type

3 dB voltage 6 dB voltage 10 dB power -20 dB voltage

—

Ratio from dB

dB → Ratio

50%

-∞ dB 0 dB +∞ dB

Ratio * Factor

Reference Type * Conversion formula

2× voltage 10× voltage 2× power 0.5× voltage

— dB

Decibels from ratio

Ratio → dB

Value * Voltage (V) or Power (W)

Unit Type * Reference level

Impedance (for dBm) Ohms (Ω)

1 mW → 0 dBm 1 V → 0 dBV 0.775 V → 0 dBu

—

Absolute dB value

Absolute dB

dBm: 0 dBm = 1 mW (50Ω) · dBV: 0 dBV = 1 V · dBu: 0 dBu = 0.775 V (600Ω)